Dual Container With Interlocking Features

ABSTRACT

An interlocking container assembly includes a first container having a first longitudinal axis and a second container having a second longitudinal axis. The first container has a male dovetail element, and the second container has a female dovetail recess that is adapted to engage the male dovetail element in order to prevent relative movement between the first and second containers in a first direction that is perpendicular to the first and second longitudinal axes. The first and second containers further respectively include a projection and a recess that are axially spaced from the respective dovetail element and female dovetail recess. The projection and the recess are adapted to engage each other in order to prevent relative movement between the first and second containers in a second direction that is parallel to the first and second longitudinal axes. The female dovetail recess is formed to have length that is favorable to fabrication using an extrusion blow molding process in which a mold is provided with a retractable mold element for forming the female dovetail recess.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a dual container assembly having two different container portions that are interlocked for handling and use.

2. Description of the Related Technology

There are many instances in which two products are meant to be used together, such as shampoo and hair conditioner, oil and vinegar, tanning cream and lotion or other various combinations of condiments or combinations of detergents. Such products are conventionally provided in two separate containers, and it is up to the consumer to make sure that the complementary products are both in the right position at the right time.

Interlocking dual containers have been proposed and have been used commercially on a limited basis. FIGS. 1 and 2 depict an interlocking dual container assembly 10 that has been used commercially. This product was characterized by two containers that are molded to have an identical shape. The bottom end of each container is provided with both a relatively narrow male dovetail element 12 and a relatively narrow female dovetail recess 14, having an opening that is about 0.26 inch in width and a maximum interior width of about 0.34 inch, which is shaped to mate with the male dovetail element of the other container. After the containers are so mated, a closure cap is applied that has the effect of binding the upper ends of the containers together, and a plastic shrink wrap label may be applied to the container assembly to further mechanically bind the two containers.

Unfortunately, the relatively narrow male dovetail element and the relatively narrow female dovetail recess of the container that is depicted in FIGS. 1 and 2 is difficult to manufacture using conventional extrusion blow molding processes because of the limited width of these elements. In addition, withdrawing the containers from the mold was difficult because of the undercut shape of the female dovetail recess, its narrow width and its relatively long axial length.

A need exists for an improved interlocking container assembly that is easier to reliably manufacturer using extrusion blow molding process then the prior art container assembly that is depicted in FIGS. 1 and 2.

SUMMARY OF THE INVENTION

Accordingly, it is an object to provide an improved interlocking container assembly that is easier to reliably manufacturer using extrusion blow molding process then the prior art container assembly that is depicted in FIGS. 1 and 2.

In order to achieve the above and other objects of the invention, an interlocking container assembly according to a first aspect of the invention includes a first container having a first longitudinal axis, the first container having a first interlocking feature; a second container having a second longitudinal axis, the second container having a second interlocking feature that is different from the first interlocking feature but that is adapted to engage the first interlocking feature in order to prevent relative movement between the first and second containers in a first direction that is perpendicular to the first and second longitudinal axes, and wherein the second interlocking feature has a width that is greater than about 0.4 inch.

According to a second aspect of the invention, an interlocking container assembly includes a first container having a first longitudinal axis, the first container having a first interlocking feature that comprises a male dovetail element; a second container having a second longitudinal axis, the second container having a second interlocking feature that comprises a female dovetail recess that is adapted to engage the male dovetail element in order to prevent relative movement between the first and second containers in a first direction that is perpendicular to the first and second longitudinal axes; the first container further comprising a third interlocking feature and said second container further comprising a fourth interlocking feature that is adapted to engage the third interlocking feature in order to prevent relative movement between the first and second containers in a second direction that is parallel to the first and second longitudinal axes.

These and various other advantages and features of novelty that characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a prior art container;

FIG. 2 is a side elevational view of the prior art container that is depicted in FIG. 1;

FIG. 3 is a cross-sectional view depicting an interlocking dual container assembly that is constructed according to a preferred embodiment of the invention;

FIG. 4 is a side elevational view of a first container in the interlocking dual container assembly that is depicted in FIG. 3;

FIG. 5 is a side elevational view of a second container in the interlocking dual container assembly that is depicted in FIG. 3;

FIG. 6 is a transverse cross-sectional view of the second container;

FIG. 7 is a transverse cross-sectional view of the first container; and

FIG. 8 is a transverse cross-sectional view taken through the interlocking dual container assembly that is shown in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to the drawings, wherein like reference numerals designate corresponding structure throughout the views, and referring in particular to FIG. 3, an interlocking dual container assembly 20 according to a preferred embodiment of the invention includes a first container 22 having a first longitudinal axis 24 and a second container 26 having a second longitudinal axis 28.

The first container 22 is shown in isolation in FIG. 4. It includes a first interlocking feature 30 that is embodied as a male dovetail element 32 that is positioned adjacent to a bottom end of the first container 22. The male dovetail element 32 is shown in transverse cross-section in FIG. 7. Unlike the prior art container that is shown in FIGS. 1 and 2, the first container 22 is constructed so that it has no female dovetail recess.

The second container 26 is shown in isolation FIG. 5. It includes a second interlocking feature 34 that is embodied as a female dovetail recess 36 that is positioned adjacent to the bottom end of the second container 26. The female dovetail recess 36 is shown in transverse cross-section in FIG. 6. Unlike the prior art container that is shown in FIGS. 1 and 2, the second container 26 is constructed so that it has no male dovetail element.

The first and second containers 22, 26 respectively include neck portions 38, 40 each having an opening defined therein that is in communication with the interior of the respective container. As is diagrammatically shown in FIG. 3, the interlocking container assembly 20 preferably includes a closure cap 42 is secured to the upper ends of the containers 22, 26 for sealing the openings in the upper ends of the containers 22, 26. The closure cap 42 also has the function of binding together the upper ends of the containers 22, 26. It may be constructed as a dispensing closure for dispensing the contents of the respective containers 22, 26.

Additionally, the interlocking dual container assembly 20 could be provided with a shrink wrap label (not shown) for providing information to the consumer and for further mechanically binding together the respective containers 22, 26.

Referring again to FIG. 4, the first container 22 further preferably includes a third interlocking feature 44, which is embodied as a projection 46. As FIG. 5 shows, the second container 26 is preferably provided with a fourth interlocking feature 48 that is preferably constructed as a recess 50 that is complementary in size and in shape to the projection 46. The projection 46 is adapted to engage the recess 50 in order to prevent relative movement between the first and second containers 22, 26 in a direction that is parallel to the longitudinal axes 24, 28 of the respective containers 22, 26.

Preferably, the recess 50 is axially spaced from the female dovetail recess 36 by a distance L_(S) that is at least 2 inches.

In order to permit a reliable molding of the female dovetail recess 36, the female dovetail recess is shaped to have a width W_(F) as shown in FIG. 6 that is greater than about 0.4 inch, and that is more preferably greater than about 0.75 inch.

Additionally, the female dovetail recess 36 preferably has an axial length L_(F) that is less than about 1 inch, and that is more preferably less than about 0.75 inch. Most preferably, the female dovetail recess 36 has an axial length L_(F) that is less than about 0.5 inch. By so limiting the axial length of the female dovetail recess, reliable manufacturing using the extrusion blow molding process is permitted despite the significant undercut that is present in the shape of the female dovetail recess 36 by using a retractable mold element in order to shape the female dovetail recess 36.

It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. An interlocking container assembly comprising: a first container having a first longitudinal axis, said first container having a first interlocking feature; a second container having a second longitudinal axis, said second container having a second interlocking feature that is different from said first interlocking feature but that is adapted to engage said first interlocking feature in order to prevent relative movement between said first and second containers in a first direction that is perpendicular to said first and second longitudinal axes, and wherein said second interlocking feature has a width that is greater than about 0.4 inch.
 2. An interlocking container assembly according to claim 1, wherein said first interlocking feature comprises a male dovetail element, and wherein said second interlocking feature comprises a female dovetail recess, and wherein both said male dovetail element and female dovetail recess have longitudinal axes that are parallel to said first and second longitudinal axes.
 3. An interlocking container assembly according to claim 2, wherein said female dovetail recess has an axial length that is less than about 1 inch.
 4. An interlocking container assembly according to claim 3, wherein said female dovetail recess has an axial length that is less than about 0.75 inch.
 5. An interlocking container assembly according to claim 4, wherein said female dovetail recess has an axial length that is less than about 0.5 inch.
 6. An interlocking container assembly according to claim 1, wherein said first container further comprises a third interlocking feature and said second container further comprises a fourth interlocking feature that is adapted to engage said third interlocking feature in order to prevent relative movement between said first and second containers in a second direction that is parallel to said first and second longitudinal axes.
 7. An interlocking container assembly according to claim 6, wherein said fourth interlocking feature is axially spaced from said second interlocking feature by a distance of at least 2 inches.
 8. An interlocking container assembly according to claim 1, wherein said second interlocking feature has a width that is greater than about 0.75 inch.
 9. An interlocking container assembly according to claim 1, wherein said first container includes no additional interlocking structure adjacent to said first interlocking feature, and wherein said second container includes no additional interlocking structure that is adjacent to said second interlocking feature.
 10. An interlocking container assembly according to claim 9, wherein said first interlocking feature comprises a male dovetail element, and wherein said second interlocking feature comprises a female dovetail recess, and wherein both said male dovetail element and female dovetail recess have longitudinal axes that are parallel to said first and second longitudinal axes.
 11. An interlocking container assembly comprising: a first container having a first longitudinal axis, said first container having a first interlocking feature that comprises a male dovetail element; a second container having a second longitudinal axis, said second container having a second interlocking feature that comprises a female dovetail recess that is adapted to engage said male dovetail element in order to prevent relative movement between said first and second containers in a first direction that is perpendicular to said first and second longitudinal axes; said first container further comprising a third interlocking feature and said second container further comprising a fourth interlocking feature that is adapted to engage said third interlocking feature in order to prevent relative movement between said first and second containers in a second direction that is parallel to said first and second longitudinal axes.
 12. An interlocking container assembly according to claim 11, wherein said fourth interlocking feature is axially spaced from said second interlocking feature by a distance of at least 2 inches.
 13. An interlocking container assembly according to claim 11, wherein said female dovetail recess has a width that is greater than about 0.4 inch.
 14. An interlocking container assembly according to claim 13, wherein said female dovetail recess has a width that is greater than about 0.75 inch.
 15. An interlocking container assembly according to claim 11, wherein said first container includes no female dovetail element.
 16. An interlocking container assembly according to claim 11, wherein said second container includes no male dovetail element.
 17. An interlocking container assembly according to claim 11, wherein said female dovetail recess has an axial length that is less than about 1 inch.
 18. An interlocking container assembly according to claim 17, wherein said female dovetail recess has an axial length that is less than about 0.75 inch.
 19. An interlocking container assembly according to claim 18, wherein said female dovetail recess has an axial length that is less than about 0.5 inch. 